In a variety of clinical situations, it is important to measure certain chemical characteristics of a patient's blood, such as pH, hematocrit, the ion concentration of calcium, potassium, chloride, sodium, glucose, lactate, creatinine, creatine, urea, partial pressure of O2 and/or CO2, and the like. These situations may arise in a routine visit to the doctor's office, in the surgical suite, intensive care unit, or emergency room. The speed with which the analytical response is obtained is important for determining therapy and therapeutic outcome. A delay in the response time of a sensor slows diagnosis, and, with it, the application of appropriate therapy. Such delays may impact prognosis and clinical outcome.
Electrochemical sensors such as those described in U.S. Pat. Nos. 6,652,720; 7,632,672; 7,022,219; and 7,972,280, the entire disclosure of each of which is incorporated herein by reference, are typically used to provide blood chemistry analysis of a patient's blood.
Conventional microelectrodes generate electrical signals proportional to chemical characteristics of the blood sample. To generate these electrical signals, the sensor systems may combine a chemical or biochemical recognition component, such as an enzyme, with a physical transducer such as a platinum electrode. Traditional chemical or biochemical recognition components selectively interact with an analyte of interest to generate, directly or indirectly, the needed electrical signal through the transducer.
The selectivity of certain biochemical recognition components makes it possible for electrochemical sensors to accurately detect certain biological analytes, even in a complex analyte mixture such as blood. The accuracy and the speed with which these sensors provide a response are important features of automated clinical analyzers.
One of the goals of clinical sample analysis system manufacturers is increasing sample throughput. Recent innovations have focused their attention on reducing the end point response time of a sensor, which is the time the sensor takes to provide an end point response. In conventional clinical analytical systems, once the sensor provides an end point response, the response is provided to a computer, which performs various mathematical operations to convert the end point response to a concentration of an analyte within the body fluid sample. The time taken for the sensor to provide an end point response dictates the time for a sample to be analyzed, which ultimately, determines the sample throughput. Accordingly, there is a need to reduce the time required to analyze a body fluid sample to expedite diagnosis and therapeutic intervention.